Sir Alex Ferguson has said he will not use the ordeal of Manchester City's 6-1 win at Old Trafford in October, the result that left him "shattered" and reflecting on "our worst ever day", as a motivational factor for his Manchester United players before Sunday's FA Cup tie.

"I will not be mentioning it," Ferguson replied when reminded of the October afternoon United were subjected to their biggest derby defeat since 1926. It is a day to which Ferguson seldom, if ever, refers and he was reluctant to join in the chorus of praise for Roberto Mancini's team, three points clear at the top of the league.

"They have a strong squad and an experienced squad so it is not unexpected where they are at the moment," Ferguson said. "But to my mind it is Tottenham who have been playing the best football in the country.

"A lot is going to happen between now and the end of the season but I can't see anyone outside the three top teams winning the league. Arsenal and Chelsea need all three teams to collapse and I don't think that will happen."

On the scale of Ferguson put-downs this was not one of his more acerbic moments against the club that United now routinely refer to as "noisy neighbours" on their club television channel. Yet his appraisal was still enough to raise quizzical looks at the Etihad Stadium. "I suppose it's difficult to say your neighbours play the best football, isn't it?" was Mancini's take, with a knowing smile. "It's hard [for Ferguson] but, until now, we have played the best football in the league. Over the next four months, I don't know. But it's been us to this point."

For the record, City have scored 56 goals, compared to Tottenham's 36, albeit having played a game more. Yet for many United supporters the real issue is that the debate does not involve the champions. Ferguson's team go into Sunday's Cup tie on the back of two demoralising defeats, against Blackburn Rovers and Newcastle United, conceding three goals in successive league matches for the first time since February 2004.

The run of bad form means United have been made 5-2 underdogs, their longest odds in a Manchester derby in Ferguson's 25 years, and though Mancini spoke this week of struggling to fill his substitutes' bench, the striker Edin Dzeko is expected to be fit after treatment for a knee injury and Samir Nasri has recovered from illness.

Ferguson's problems with absenteeism are more acute, with eight players missing through injury or illness, and the United manager said it could be considered a success that his team were only three points behind City.

"We can say in some respects: 'Well done, to be there.' The advantage on Sunday is with City, in respect of it being a home draw. But it's a Cup tie, a derby and anything can happen in these games."

Ferguson's long-standing admiration for Frank Lampard has led to the Chelsea midfielder being informed United would be interested if, as increasingly looks the case, he were to be available. The 33-year-old is keen on the idea but Ferguson said it was unrealistic to believe United would try to sign Lampard in January and reiterated that it was unlikely United would sign anyone in the transfer window.

"What can you get in January? The players who are available that we like we won't get. And you are not going to tell me that Chelsea are going to sell Lampard to Manchester United in January, do you really believe that?

"There is no foundation to that simply because Chelsea are like us and want to do something. The second half of the season is important to them and if they want to try to win the league they are going to have to have all their best players. And that is the name of the game, the players we do like we won't get. What do you do? Do you take a second-rate player? No, of course you don't."

Ferguson was unwilling to discuss the reasons behind dropping Wayne Rooney for the Blackburn game and fining him a week's wages, because the striker seemed worse for wear in training after a night out. "I'm not getting into that," he said. A reporter pointed out it was a valid question and Ferguson replied: "Well, you got your answer."

Last night the club and Rooney issued a joint statement denying the England striker is about to leave. Stories have emerged claiming the 26-year-old's relationship with Ferguson has broken down. This has been denied by both parties.

"Manchester United and Wayne Rooney have been made aware of the theme of an article in tomorrow's Independent newspaper," said the statement. "We have not seen the detail but can assure all United fans that the manager and the club are committed to Wayne Rooney and Wayne is committed to the manager and the club.

"The player and the manager have always had and retain, the utmost respect for each other and look forward to working together in the coming seasons.

"Any suggestion that Manchester United and Wayne Rooney are to part company is complete nonsense."

But the tersest moment came when asked about Liverpool wanting clear-the-air talks over the Luis Suárez affair. "It's nice of them to do it through the press," he said pointedly. "You would have thought they would have come to Manchester United."